const RE_NARGS = /(%|)\{([0-9a-zA-Z_]+)\}/g

export default function() {
  function hasOwn(obj, key) {
    return Object.prototype.hasOwnProperty.call(obj, key)
  }
  function template(string, ...args) {
    if (args.length === 1 && typeof args[0] === 'object') {
      args = args[0]
    }
    if (!args || !args.hasOwnProperty) {
      args = {}
    }
    return string.replace(RE_NARGS, (match, prefix, i, index) => {
      let result
      if (string[index - 1] === '{' && string[index + match.length] === '}') {
        return i
      } else {
        result = hasOwn(args, i) ? args[i] : null
        if (result === null || result === undefined) {
          return ''
        }
        return result
      }
    })
  }
  return template
}
